From Thioxo Cluster to Dithio Cluster: Exploring the Chemistry of Polynuclear Zirconium Complexes with S,O and S,S Ligands

Three different zirconium thio and oxothio clusters, characterized by different coordination modes of dithioacetate and/or monothioacetate ligands, were obtained by the reaction of monothioacetic acid with zirconium n-butoxide, Zr(OnBu)4, in different experimental conditions. In particular, we isolated the three polynuclear Zr3(¼3-SSSCCH3)2-(SSCCH3)6 (3) 2nBuOH (Zr3), Zr4(¼3-O)2(¼-·1-SOCCH3)2(SOCCH3)8(OnBu)2 (Zr4), and Zr6(¼3-O)5(¼-SOCCH3)2-(¼-OOCCH3)(SOCCH3)11(nBuOH) (Zr6) derivatives, presenting some peculiar characteristics. Zr6 has an unusual star-shaped structure. Only sulfur-based ligands, viz., chelating dithioacetate monoanions and an unusual ethane-1,1,1-trithiolate group ¼3 coordinating the Zr ions, were observed in the case of Zr3. 1D and 2D NMR analyses confirmed the presence of differently coordinated ligands. Raman spectroscopy was further used to characterize the new polynuclear complexes. Time-resolved extended X-ray absorption fine structure measurements, devoted to unraveling the cluster formation mechanisms, evidenced a fast coordination of sulfur ligands and subsequent relatively rapid rearrangements.